Content-type: text/html Manpage of fft

fft

Section: User Commands (1)
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NAME

fft - Fourier transform on image(s)  

PERSON RESPONSIBLE

mchw  

CATEGORIES

uv analysis, map making  

DESCRIPTION

FFT is a MIRIAD task which performs a fast Fourier transform on an image. If the input is a cube, then each plane is FFT'ed individually (i.e. this does not perform a 3D FFT).

Blanked pixels in the input images are treated as if the pixel was zero. If the input image is not a power of two in side, the image is blank padded up to a power of two.

The output of the FFT would normally be complex valued. You can save the output in any one of several ways -- as the real or imaginary part, or as the magnitude (amplitude) and phase.  

PARAMETERS

rin
This gives the input real part image. No default.
iin
This gives the input imaginary part image. The default is a zero image.
sign
This gives the sign of the exponent in the transform. -1 gives a forward transform, +1 an inverse transform. An inverse transform applies 1/N scaling. The default is a forward transform.
center
This gives the origin of the transform. If two values are given, then they are used as the origin in the x and y axis respectively. If one value is given, then this is used for the origin for both the x and y dimensions. The default is the header value for CRPIX1 and CRPIX2 (if they are in the header) or N/2+1 (if CRPIX is missing from the header).
rout
The output real part image. The default is not to write this image out.
iout
The output imaginary part image. The default is not to write this image out.
mag
The output magnitude (amplitude) image. The default is not to write this image out.
phase
The output phase image. The default is not to write this image out.


 

Index

NAME
PERSON RESPONSIBLE
CATEGORIES
DESCRIPTION
PARAMETERS

This document was created by man2html, using the manual pages.
Time: 18:35:38 GMT, July 05, 2011